Bladder cancer patients with various stages of disease underwent immune evaluation with skin testing and in vitro lymphocyte studies. As tumor burden increased, there was a higher percentage of negative skin tests. Those responses which correlated best with stage of disease were DNCB (p less than .001), and croton oil inflammatory response (p less than .001). None of the skin tests correlated closely with survival although there was a trend toward longer survival in DNCB responders. DNCB response did relate to the tumor-free interval. Responders had a longer tumor-free interval than non-responders. In vitro tests of lymphocyte function are still being evaluated. New tests for cytotoxic and regulatory functions are being introduced to assess the impact of bladder cancer, radiotherapy, and chemotherapy on host immune functions. Immunotherapy with levamisole is being evaluated in a randomized study of several stages of transitional cell cancer ofthe bladder.